Well, heres the thing... If you get Applecare, your Mac will be in perfect health and will probably never use it. But if you don't, you will probably wish you had at some point... But overall, it's a good value, especially if some expensive part fries... Like the display or motherboard... Also, keep in mind, with the new iMacs, to service them yourself you will need to buy special thermal paste and clean/apply it to parts EVERY time... it's nicer to leave this to professionals...
pnw